1. Field of the Invention
The present invention relates to a stator of an electric motor which is provided with a coil fastening part which fastens a unit coil which is arranged at a tooth of a core, an electric motor, and a fastening method which fastens a unit coil.
2. Description of the Related Art
In an electric motor which is provided with a unit coil, when the unit coil is attached to a tooth of a laminated core, a fine gap which is surrounded by the inner surface of the unit coil and the outer surface of the tooth is formed on either side of the tooth in the lamination direction of the laminated core. This gap can become a cause of detachment of the unit coil from the tooth after attachment of the unit coil, so a separate fastening step for fastening the attached unit coil to the tooth is considered necessary. In the conventional fastening step, various techniques were used to fasten the unit coil to the tooth.
For example, in the art which is described in JP-A-2013-031252, a heat foaming member was inserted in the clearance between the unit coil which was attached to the tooth of the stator and the heat foaming member was made to expand by heat so as to fasten the unit coil to the stator. Further, in the art which is described in JP-A-2010-246269, an insulator which has tabs which engage with the end face of the unit coil is attached to the tooth of the stator so as to fasten the unit coil to the stator. However, in the art which is described in JP-A-2013-031252, it is necessary to heat the heat foaming member, so the workability when fastening the unit coil falls. Further, in the art which is described in JP-A-2010-246269, it is necessary to prepare a complicatedly shaped insulator as a fastening part of the unit coil and necessary to additionally work the laminated core.
A stator of an electric motor which can improve the workability when fastening the unit coil to the tooth is sought.